Continuous prepress for fiberboard plant

ABSTRACT

A prepress for a fiberboard plant has a plurality of upper rollers spaced above a plurality of lower rollers. The lower rollers are fixed in a rigid support frame and the upper rollers are fixed by pairs in respective upper support frames each comprising a pair of longitudinal beams embracing two rollers and a pair of transverse beams bridging the longitudinal beams and each adjacent one of the rollers. Each upper roller is journaled at one end in one of the longitudinal beams in a self-aligning bearing permitting transverse displacement of the roller relative to that longitudinal beam and at its other end in a conventional self-aligning bearing. Each transverse beam has one end fixed to one of the longitudinal beams and another end secured by means of a ball joint to the other longitudinal beam. A plurality of hydraulic cylinders each have one end secured to the support of the lower rollers and another end secured to an insert fitted within the end of a transverse beam. In this manner it is possible for the rollers at opposite ends of the frame to be tilted in opposite directions and the distortion so produced does not damage the frames due to the provision of the various selfaligning bearings and ball joints.

United States Patent [1 1 Reiners CONTINUOUS PREPRESS FOR FIBERBOARD PLANT [75] Inventor: Wolfgang Reiners, Kapellen Kreis Moers, Germany [73] Assignee: G. Siempelkamp & Co., Krefeld,

Germany [22] Filed: Apr. 3, 1974 [2]] Appl. No.: 457,626

3,784,340 1/1974 Kerttula et al.. 425/371 X 3,795,470 3/1974 De Mets 425/371 3,827,846 8/1974 Weiler 425/371 Primary Examiner-J. Howard Flint, Jr. Attorney, Agent, or Firm-Karl F. Ross; Herbert Dubno [5 7] ABSTRACT A prepress for a fiberboard plant has a plurality of upper rollers spaced above a plurality of lower rollers. The lower rollers are fixed in a rigid support frame and the upper rollers are fixed by pairs in respective upper support frames each comprising a pair of longitudinal beams embracing two rollers and a pair of transverse beams bridging the longitudinal beams and each adjacent one of the rollers. Each upper roller is journaled at one end in one of the longitudinal beams in a self-aligning bearing permitting transverse displacement of the roller relative to that longitudinal beam and at its other end in a conventional selfaligning bearing. Each transverse beam has one end fixed to one of the longitudinal beams and another end secured by means of a ball joint to the other longitudinal beam. A plurality of hydraulic cylinders each have one end secured to the support of the lower rollers and another end secured to an insert fitted within the end of a transverse beam. In this manner it is possible for the rollers at opposite ends of the frame to be tilted in opposite directions and the distortion so produced does not damage the frames due to the provision of the various self-aligning bearings and ball joints.

6 Claims, 6 Drawing Figures CONTINUOUS PREPRESS FOR FIBERBOARD PLANT CROSS REFERENCE TO RELATED APPLICATIONS This application is related to the commonly assigned copending application Ser. No. lO9,l98 filed on Jan. 25, 1971 by Gerhard Hutz and entitled METHOD OF AND APPARATUS FOR MAKING LAMINATED PRESSBOARD, itself of a continuation in part of the application of Gerhard Hutz issuing on Apr. 27, 1971 as US. Pat. No. 3,576,692.

Field of the Invention The present invention relates to a band press. More particularly this invention relates to a prepress used for the compression of a mass of coherent fibers or the like to a dense band.

Background of the Invention In the production of laminated pressboard of fiberboard, fibers are deposited in layers on a moving conveyor belt and the layers so formed are prepressed into a coherent mat which is then finished pressed in a multiplaten press to form rigid boards. It is possible to press the mat between laminate sheets in the final press so as to form a finished board useful for paneling and similar purposes. Such an installation is also described in the commonly assigned US. Pat. No. 3,61 1,482 granted on Oct. 12, 1971 to Gerhard I-Iutz.

Formation of a band of uniform width has proven extremely difficult in practice. It is necessary that the mats, once the band is subdivided into separate sections, be of relatively uniform density so that when they are finish pressed the board is of even strength. Attempts have been made to accomplish this at the prepressing stage, where the incoherent mass of fibers on the conveyor belt is pressed into a relative cogerent band.

One type of prepress well known in the art has at least two longitudinally spaced upper rollers and at least two longitudinally spaced lower rollers, with pressing bands stretched over these rollers. The conveyor belt runs between the two bands and the rollers exert compressive force on the mass of fibers carried on the conveyor belt. In this manner the thickness of the mass of fibers is reduced considerably and heat is usually applied so as to activate a binder mixed with the fibers and thereby form the coherent mats. It is known in this type of press to compensate for the variation in the thickness of the band of fibers fed into it by tilting one of the pairs of rollers relative to the other pair to produce a precompressed mass which is of even density. The problem with this type of arrangement is that with known systems of depositing the fibers to conveyor belts the band so formed is of wedge cross section, with sometimes one side thicker than the other and sometimes the other depending on deposition rates and various other virtually uncontrollable factors. Thus if one side of the band is thick and then is followed for a short region by a thin area and then by another thick area it is impossible for the prepress to compensate quickly in order to produce a prepressed mat of even density.

OBJECTS OF THE INVENTION It is therefore an object of the present invention to provide an improved press. Another object is the provision of an improved prepress for use in an installation for producing fiberboard and the like. 5

Yet another object is the provision of an improved frame for carrying the rollers of a band-type prepress which overcomes the above given disadvantages.

SUMMARY OF THE INVENTION These objects are attained according to the present invention in a prepress of the above-described general type, that is having a pair of longitudinally and horizontally spaced upper rollers and a pair of longitudinally horizontally spaced lower rollers with an upper band spanned around the upper rollers and a lower band spanned around the lower rollers wherein at least one of the pairs of rollers, generally the upper pair is mounted between a pair of longitudinally extending and generally horizontal beams that embrace this upper pair. At least two transversely extending beams interconnect the longitudinally extending beams so as to form a frame. According to this invention a selfaligning bearing is provided at each end of each of the upper rollers to journal it in the respective longitudinal beams, and one of the bearings of each roller is arranged so as to permit limited transverse relative displacement between the respective roller and the respective longitudinal beam. In addition the transverse beams each have one end rigidly fixed to one of the longitudinal beams and another end connected to the other longitudinal beam by means of a ball joint. A plurality of longitudinally based extensible elements, such as hydraulic cylinders, are engaged between the support in which the lower rolls are journaled and the frame carrying the upper rollers. Thus it is possible individually to tip these upper rolls so as to exert even arresting force which can vary from one end to the other of the prepress, since it is possible for the frame to be distorted, with one of the upper rollers tilted to the horizontal in one direction and the other tilted in the opposite direction if necessary.

Thus according to the present invention it is possible effectively to provide a separate control for each of the rollers, thereby allowing adjustment of each roller, rather than requiring adjustment of the entire assembly as has been hitherto known. The arrangement using ball joints and self-aligning bearings prevents the frame holding the upper rollers from becoming damaged from frequent distortion.

In accordance with a further feature of the invention the transverse beams are hollow and have ends each receiving an outwardly projecting insert, the one insert projecting through the end rigidly connected with one longitudinal beam and the other insert projecting through the ball joint securing it to the other longitudinal beam. The hydraulic jacks serving to adjust the press are connected to these inserts, so that the force is transmitted from the transverse beams to the longitudinal beams and thence to the rollers, giving an extremely advantageous force distribution. The transverse beams are arranged alternately, that is with the ball joint of one being being secured in one longitudinal beam and the ball joint of the neighboring transverse beam being carried in the other longitudinal beam, so as to permit maximum possible distortion of the frame.

According to yet another feature of this invention transverse stabilizing elements are provided in pairs to either side of each transverse beam each having one end connected adjacent the ball joint of the respective transverse beam and another end connected to the op posite longitudinal beam, with the two stressing elements at each transverse beam forming a'V opening outwardly towards the longitudinal beam corresponding to the rigidly fixed end of the respective transverse beam.

DESCRIPTION OF THE DRAWING The above and other objects, features, and advantages will become more readily apparent from the following with reference to the accompanying drawing in which:

FIG. 1 is a side elevational view of a press according to the present invention;

FIG. 2 is an end view partly in section and taken in the direction of arrow II FIG. 1;

FIG. 3 is a perspective view of the upper frame carrying two of the upper rollers; and

FIGS. 4, 5 and 6 are sections taken along lines IVIV, VV, and VI-Vl of FIG. 3.

SPECIFIC DESCRIPTION As shown in FIG. 1 the press according to the present invention has a lower roller assembly 1 and an upper roller assembly 2 respectively comprising leading rollers 3' and 3, trailing rollers 4' and 4 and central rollers 8' and 8. Band 6' is spanned over the three lower rollers 3', 8 and 4' as well as over support rollers 5' carried on beams 22' and over various tension rollers 5' carried on beams 22' and over various tension rollers 23. Another band 6 is spanned over the three main upper rollers 3, 8, and 4, as well as over the support rollers 5 carried on beams 22 and over tensioning rolls 23. The lower rollers 3', 8', and 4' are all rigidly journaled on a single heavy duty support frame 24. Transmissions 25 and 25' serve to drive the rollers 8 and 8' respectively as shown in FIG. 2. Dot-dash line 26 indicates the path of a deposition belt on which fibers or chips are deposited to form an incoherent band pressed into a coherent band by the prepress according to the present invention.

Eight hydraulic cylinders 27 are provided between the support beams 22 and the frame 24 so as to allow the support rollers 5 to be displaced according to the present invention.

The rollers 3, 8, and 4, are supported on a pair of frames 10 formed of a pair of longitudinally extending beams 11 and a pair of transversely extending beams 12. As shown in more detail in FIGS. 2 and 3 the longitudinally extending beam 11 are of rectangular section and the beams 12 are of circular section, both of the beams 11 and 12 being hollow and made of steel. The rollers 4 and 8 are journaled in the longitudinal beam 11 in identical fashion. FIG. 6 shows the mounting of roller 8, wherein this roller is formed at its end with bearing 19 is arranged in a sleeve 19a permitting limited displacement of the bearing 19 relative to the beam 11 in a direction transverse to this beam 11. The rollers 3, 4, and 5 are similarly mounted.

Each transverse beam 12 has at one end 12' a pair of rigid steel gussets 14 which are welded in place to connect this end 12' securely to the respective longitudinal beam 11, as shown in more detail in FIG. 4. The other end 12" of the tube 12 is fitted with an insert 21 welded securely in place within it and provided with a ball surface 15 held in place by a nut 28 and received within a socket 16 held by a snap ring 29 in the respective beam 11. Thus it is possible for the beam 12 to move so that the rollers can be displaced as shown by the dotdash lines independently of each other. This motion is effected by hydraulic cylinders 13 having their cylinder members 13a secured to the frame 24 and their piston rods 13b connected to either the insert 21 shown in FIG. 5 or an insert 30 shown in FIG. 4, this latter insert 30 being welded in place within the end 12 of the tube 2. These cylinders 13 as well as the cylinders 27 are all connected to a control unit 31 shown in FIG. 1 which is operated by sensors (not shown) to regulate the pressure exerted by the press on the band of fibers as it is brought through the press on the conveyor belt 26. The beams 22 and 22' of rollers 5 and 5 are similarly interconnected.

The two frames 10 allow the front region of the press as shown at double-headed arrow 18 to be spread so as to form a mouth tapered in the upstream direction whereas the upstream section 17 has the rollers generally evenly spaced apart. Of course the control means is operated to compensate for various different thicknesses in the band strewn on the conveyor belt 26.

Such an arrangement allows the press to compensate almost instantly for any difference in thickness of the strewn band of fibers. In fact it allows one of the rollers to be tipped in one direction while the other is tipped in the opposite direction without undue stress of the frames 10. Such an arrangement allows the production of a prepressed mass of uniform density over its entire area.

I claim:

1. A roller frame for a continuous band press, said frame comprising:

a pair of longitudinally extending generally horizontal beams;

a pair of transversely extending generally horizontal beams bridging said longitudinal beams;

means rigidly fixing one end of each transverse beam to a respective one of said longitudinal beams;

a ball joint between the other end of each transverse beam and the other respective longitudinal beam;

a pair of generally parallel horizontally spaced rollers received between said longitudinal beams generally at the ends thereof;

a self-aligning bearing rotatably holding each end of each roller on the respective longitudinal beam; and

means for limited transverse displacement between each roller and a respective longitudinal beam.

2. The frame defined in claim 1 wherein said press includes a second pair of rollers spaced vertically from the first-mentioned pair of rollers, a support for said second pair, and a plurality of upright vertically extensible hydraulic cylinders between said support and said frame.

3. The frame defined in claim 2 wherein each of said cylinders has an end connected to a respective end of a respective a respective one of said transverse beams.

6. The frame defined in claim 5 wherein said stressing elements are arranged in pairs having their said one ends connected relatively closely together to said one longitudinal beam to either side of said means rigidly fixing said transverse beam to said one longitudinal beam and their said other ends connected to said other longitudinal beam relatively far apart to either side of the ball joint of the respective transverse beam. 

1. A roller frame for a continuous band press, said frame comprising: a pair of longitudinally extending generally horizontal beams; a pair of transversely extending generally horizontal beams bridging said longitudinal beams; means rigidly fixing one end of each transverse beam to a respective one of said longitudinal beams; a ball joint between the other end of each transverse beam and the other respective longitudinal beam; a pair of generally parallel horizontally spaced rollers received between said longitudinal beams generally at the ends thereof; a self-aligning bearing rotatably holding each end of each roller on the respective longitudinal beam; and means for limited transverse displacement between each roller and a respective longitudinal beam.
 2. The frame defined in claim 1 wherein said press includes a second pair of rollers spaced vertically from the first-mentioned pair of rollers, a support for said second pair, and a plurality of upright vertically extensible hydraulic cylinders between said support and said frame.
 3. The frame defined in claim 2 wherein each of said cylinders has an end connected to a respective end of a respective a respective one of said transverse beams.
 4. The frame defined in claim 3 wherein said transverse beams are hollow and provided at each of their ends with rigid inserts, the insert at one end carrying said ball joint and the insert at the other end projecting through the respective longitudinal beam.
 5. The frame defined in claim 2, further comprising elongated stressing elements each having one end secured in one of said longitudinal means and another end in the other longitudinal beam, said elements extending at an angle to said transverse beams.
 6. The frame defined in claim 5 wherein said stressing elements are arranged in pairs having their said one ends connected relatively closely together to said one longitudinal beam to either side of said means rigidly fixing said transverse beam to said one longitudinal beam and their said other ends connected to said other longitudinal beam relatively far apart to either side of the ball joint of the respective transverse beam. 